The present invention relates to a new and improved construction of a comminuting machine.
In its more particular aspects, the present invention specifically relates to a new and improved construction of a comminuting machine for comminuting waste and, more particularly, waste wood material intended to be composted. Generally, such machines are mounted at a mobile support frame and comprise a housing in the form of a container for receiving the material to be comminuted. A conveyor is disposed in the housing or container for conveying the infed material to a rotary impact mechanism. The rotary impact mechanism cooperates with an impact plate in a comminuting section which precedes a discharge opening of the housing or container for discharging the comminuted material under the action of the rotary impact mechanism. The impact plate may be followed by further comminuting means through which the comminuted material is discharged with further comminution. The comminuted material may be deposited in stacks or pits for composting.
A comminuting machine or composting equipment such as known, for example, from U.S. Pat. No. 4,852,816, granted on Aug. 1, 1989, to the applicant of the instant application, is constructed for comminuting organic or wood waste originating in forestry, municipality or building operations. A trough-shaped container receives the material to be comminuted, for example, by means of a shovel loader. Infeed means are provided in the form of an infeed conveyor which is located above the bottom of the container and feeds the material to a rotary impact mechanism which drives the infed material through an entrance gap defined between an impact ledge and rotating flails of the rotary impact mechanism. The impact ledge is followed by retainer claws which extend between adjacent ones of the rotating flails for comminuting the material which has been forced through the entrance gap. An impact plate follows the retainer claws and has teeth protruding toward the rotating flails and cooperating therewith for further comminuting the material prior to its discharge through a discharge opening from a rear part of the container.
In a further development (Doppstadt shredder, type AK 330) of the aforementioned comminuting machine the infeed means further include an intake roll which bears upon the infed material from above. The entrance gap is followed by an impact plate containing two plate sections. The two plate sections are arranged at an angle with respect to each other so that the impact plate extends along an upper part of the cylindrical action area of the rotating flails. Teeth protrude from the impact plate toward the rotating flails and are arranged in parallel rows transverse with respect to the rotational direction of the rotating flails, the rows of teeth being transversely offset from each other. There is thus defined a throughpass gap through which the incoming material is forced under the action of the rotating flails and subjected to comminuting action. The impact plate may be immediately followed by further comminuting means disposed laterally of the rotating flails at the discharge opening of the container. This further comminuting means is formed by a frame containing upper and lower traverses; generally arcuately shaped struts extend between the upper and lower traverses in a spaced parallel relationship to each other and have teeth protruding upwardly in opposition to the rotating flails. The comminuted material is thereby subjected to further comminution and forced out through the spaces existing between the struts. The further comminuting means is pivotally mounted by means of the upper traverse.
In both of the aforementioned comminuting machines the impact plate as well as the further comminuting means are pivotably supported so as to pivot away from the rotating flails in the event that the infed material contains pieces of material which do not disintegrate under the action of the rotating flails in cooperation with the impact plate. The rotary impact mechanism and the impact plate are thus prevented from damage by pieces of non-disintegratable material. Hydraulic displacement means are provided in the Doppstadt AK 330 shredder on the outer side of the impact plate and linked to the further comminuting means for displacing the same between an operative position, in which the container discharge opening is covered thereby, and an inoperative position, in which the further comminuting means is pivoted away from the container discharge opening.
Furthermore, both of the aforementioned comminuting machines are mobile machines mounted at a support frame on wheels. Such wheel support can be provided by supporting the comminuting machine on a truck such as known from European Patent No. 0,212,194, the grant of which to the applicant of the instant application was published on Oct. 11, 1987; in such construction the engine of the truck also serves to drive the comminuting machine. The wheel-supported support frame may also carry the drive means for operating the comminuting machine; as described in the aforementioned U.S. patent, such comminuting machine may be displaced at the given working location by means of the shovel loader used for charging the comminuting machine. The support frame may also be supported at a tandem axle. Pressure fluid operated drive means acting upon the front wheels of the tandem axle may be provided for displacing the comminuting machine at the working location (Doppstadt shredder AK 330). Remote control means may be used for controlling the operation of the comminuting machine including the pressure fluid operated drive means. While the machine can be operated in this manner independent of a truck, travel to a different working location requires connection to a towing vehicle like a tractor or truck.
Still further, both of the aforementioned mobile comminuting machines are equipped with an overload coupling and/or overload control means which are responsive to deceleration of the rotary impact mechanism in the presence of excessive infed material to be comminuted. Such overload coupling mainly serves to dampen rapid transient variations in the rotational speed of the rotary impact mechanism due to a momentary overload so that the same do not or only little affect the prime mover. The overload control means react to the overload by decelerating and eventually stopping the infeed drive means as a function of the rotational speed of the rotary impact mechanism.
A stationary comminuting machine such as known, for example, from German Published Patent Application No. 2,902,257, published on Jul. 31, 1980, is intended for comminuting particularly confidential files but also waste materials of any kind including waste wood. Infeed means like infeed rolls feed the material to be comminuted to an inlet gap and into the interior of the drum-like housing. Parts of the infed material protrude through the inlet gap and are severed or chopped off by a rotary impact mechanism. The drum-like housing of the comminuting machine accommodates a basically segment-shaped impact body defining a throughpass gap in cooperation with the rotary impact mechanism. The throughpass gap narrows from an inlet for infeeding the material to be comminuted to an outlet and extends around the upper half of the rotary impact mechanism. The impact body is mounted at the drum-like housing by means of bolts permitting adjustment of the impact body in radial direction relative to the rotary impact mechanism. At its rear end, as viewed in the rotational direction of the rotary impact mechanism, the impact body bears upon a stop. The impact body is provided on its inner side with, for example, a saw-tooth profile which extends parallel to the axis of the rotary impact mechanism. The impact body is followed, in the rotational direction of the rotary impact mechanism, by grate means which extends around the lower half of the rotary impact mechanism and defines a throughpass gap which narrows in the rotational direction.
A stationary comminuting machine or pulverizer such as known, for example, from U.S. Pat. No. 1,125,137 is constructed as a hammer mill into which the material to be comminuted is dropped from the top. The incoming material is hit by a rotary shaft with spiders extending radially therefrom and provided with swinging hammers at their free ends. The hammers cooperate with different breaking plates extending in sequence around part of the circumference defined by the rotating hammers. A first breaking plate presents a smooth surface to the rotating hammers; a second breaking plate is provided with a sequence of teeth formed by faces which rise from the plate in the direction of rotation of the rotating hammers; a third breaking plate extends along the lower half of the circumference described by the rotating hammers and contains a number of bars arranged at an angle relative to the associated faces of the rotating hammers. The spaces between the bars serve as discharge openings for the comminuted material. A section of the support structure for the bars of the third breaking plate can be pivoted away from the circumference described by the rotating hammers by manually operated pivot means in order to permit removal of material which can not be sufficiently reduced.
A further stationary comminuting machine or reduction mill such as known, for example, from U.S. Pat. No. 4,226,375, granted Oct. 7, 1980, is also constructed in the manner of a hammer mill into which the material to be comminuted is dropped from the top. The incoming material is hit by a rotary body from which the hammers protrude in essentially radial direction. An anvil wall extends along a lower quadrant of the rotary body and defines a channel which narrows in the rotary direction of the rotary body. The anvil wall is immediately followed by a grate section extending laterally of the rotary body over an angle of 140.degree. to 170.degree.. The grate section cooperates with the rotating hammers in a manner such that the infed material is further comminuted and forced through screen openings of the grate section. The grate section is formed by a circumferentially sequential assembly of cutter bars and screen bars which are mounted in a common housing. The housing can be pivoted away from the rotary body in order to permit access for maintenance and repair operations on the grate section and the hammers.
In a further known stationary comminuting machine such as a hammer mill known from USSR Author Certificate No. 1,230,678, published May 15, 1986, the material to be comminuted is dropped from the top onto rotating hammers of a rotor which cooperate first with an impact plate which is arranged above the rotating hammers and extends generally in the direction of rotation of the rotating hammers. The impact plate is provided with transversely and lengthwisely extending ribs protruding toward the rotating hammers. A second impact plate follows the first impact plate at an obtuse angle relative thereto; this second impact plate is provided with angular impact elements defining tips which are directed toward the rotating hammers. This second impact plate is immediately followed by a third, planar impact plate downwardly inclined toward the rotor. Finally, a grate immediately follows the third impact plate and semicylindrically surrounds the lower half of the rotor. The comminuted material is forced and discharged through the grate under the action of the rotating hammers.
Contrary to the first mentioned mobile waste comminuting machines, the last mentioned stationary comminuting machines are not provided with any means permitting the impact plates and other structures which cooperate with the rotating hammers, to yield in the presence of non-disintegratable material.
Regarding the aforementioned mobile waste comminuting machines, the comminuting actions realized therein have been found to be unsatisfactory not only with respect to the further comminuting effect which can be achieved after the material has been forced past the impact plate, but also with respect to the insufficient variability in adaptation to the material to be comminuted and the overall extent of the achievable comminution. Thus, for example, the degree of comminution required for a subsequent composting process is higher than the degree of comminution required for the disintegration of wood waste like boarding.